<template>
    <view class="scroll-view-container">
      <!-- 左侧的滚动视图区域 -->
      <scroll-view class="left-scroll-view"  scroll-y :style="{height: wh + 'px'}">
        <block v-for="(item, i) in cateList" :key="i">
          <view 
           :class="['left-scroll-view-item', i === active ? 'active' : '']" 
           @click="activeChanged(i)"> {{item.cat_name}}
          </view>
        </block>
      </scroll-view>
      <scroll-view class="right-scroll-view" scroll-y  :scroll-top="scrollTop" :style="{height: wh + 'px'}">
        <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
           <!-- 三级分类 -->
            <view class="cate-lv3-list">
            <view class="cate-lv3-item" 
                  @click="gotoGoodsList(item3)" 
                  v-for="(item3, i3) in item2.children"
                  :key="i3">
              <image :src="item3.cat_icon"></image>
              <text>{{item3.cat_name}}</text>
          </view>
          </view>
        </view>
      </scroll-view>
    </view>
</template>

<script>
  export default {
    data() {
      return {
        wh: 0,
        active: 0, // 默认选中
        scrollTop: 0, //滚动条距离
        cateList:[], // 分类列表
        cateLevel2:[] // 二级分类列表
      };
    },
    onLoad() {
     // 获取当前系统的信息
         // https://uniapp.dcloud.io/api/system/info?id=getsysteminfosync
         try {
           const res = wx.getSystemInfoSync()
           this.wh = res.windowHeight
           console.log(this.wh)
         } catch (e) {
           // Do something when catch error
         }
      this.getCateList()
    },
    methods:{      
      // 默认选中 
       activeChanged(i) {
        this.active = i
        this.cateLevel2=this.cateList[i].children
        this.scrollTop = this.scrollTop ? 0 : 1
        console.log('scrollTop',this.scrollTop)
      },
      // 左侧的滚动视图区域
      async getCateList(){
        const {data:res} = await uni.$http.get('/categories') 
        if(res.meta.status!==200) return uni.$showMsg ()
         console.log('getCateList',res)
         this.cateList=res.message
         this.cateLevel2=res.message[0].children
      },  
      gotoGoodsList(item3){
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
           })
         }
    }
  }
</script>

<style lang="scss">
.scroll-view-container {
  display: flex;
  .left-scroll-view {
    width: 120px;
    .left-scroll-view-item {
      line-height: 60px;
      background-color: #f7f7f7;
      text-align: center;
      font-size: 12px;
      // 激活项的样式
      &.active {
        background-color: #ffffff;
        position: relative;
        // 渲染激活项左侧的红色指示边线
        &::before {
          content: ' ';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #c00000;
          position: absolute;
          left: 0;
          top: 50%;
          transform: translateY(-50%);
        }
      }
    }
  }
 .cate-lv2-title {
   display: flex;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    padding: 15px 0
 }
 .cate-lv3-list {
   display: flex;
   flex-wrap: wrap;
   .cate-lv3-item {
     width: 33.33%;
     margin-bottom: 10px;
     display: flex;
     flex-direction: column;
     align-items: center;
     image {
       width: 60px;
       height: 60px;
     }
     text {
       font-size: 12px;
     }
   }
 }
}
</style>
